The average kinetic energy of all particles is directly proportional to the absolute temperature.

At a fixed temperature, all the particles do not have the same kinetic energy. They do not travel at the same speed $\rightarrow$ there is a spread in the kinetic energy of the particles, i.e. some particles are very fast while some particles are slow.

Take note: The third and fourth point do not contradict each other. In fact, with the fourth point in place, the third point is redundant.

Kinetic comes from Greek word “kineo” meaning motion (movement). Kinetic theory explains the movement of particles of matter, attraction force btn the states and temperature effect on them.It is summarised by four statements: 1.Matter is made up of tiny particles. 2.The particles are in constant motion. 3.There is attraction force btn the particles. 4.Temperature has an effect on them.